let/obj={
  a: 1,
  b: 2,
  c: 3,
}

const/{
  a,
  ...partialObj
}=obj

.obj -- ${JSON.stringify(obj)}
.partialObj -- ${JSON.stringify(partialObj)}
.a -- ${a}
.b -- ${partialObj.b}
.a -- ${partialObj.a === undefined ? "removed a" : "didn't remove a"}

button onClick() {
  obj = {
    a: 4,
    b: 5,
    d: 6
  }
} -- Update
